CTO Responsibilities in a 2–5-Dev Seed/Pre-Seed Startup

16 Oct 2025

What your CTO must do today

Ship or unblock: write/review code and keep delivery moving.
Own architecture: make stack/structure choices that avoid chaos later.
Mentor & set norms: code reviews, CI, testing basics, calm comms.
Security & reliability floor: auth, logging/alerts, backups, runbooks.
Bridge tech ↔ product ↔ founders: translate goals, trade-offs, timelines.

Get these five right every week; everything else is secondary but important.

The Human CTO in a 5-Person Team: role at a glance

You’re both builder + leader. You will still code, debug, deploy—while shaping direction, culture, and scalability.

Pillar	Responsibility	Why it matters now
Build & Ship	Write key features, review PRs, enforce CI	Early momentum; avoid rework.
Architecture & Tech Strategy	Choose stack, module boundaries, build vs. buy	Bad early choices become debt.
Team & Culture	Hire first engineers, mentor, set review norms	Culture seeds early; codebase follows.
Security & Reliability	Basic auth, logging/alerts, backups, runbooks	Minimizes avoidable incidents.
Cross-Stakeholder Communication	Translate tech ↔ business; short arch docs	You are the glue for decisions.
Fundraising & Tech Narrative	Diligence docs, moat, scaling plan	Investors will probe your design.

CTO Stage Map: 2–5 Devs (Original Checklist Asset)

Use this weekly self-audit to align what you should be doing vs what you did.

Team size	Focus this week	Sample tasks / deliverables
2 devs	Build foundation, set norms	Ship core MVP endpoint, style guide, CI pipeline.
3 devs	Introduce ownership, guardrails	Delegate a feature, enforce code reviews, start internal wiki.
4 devs	Start specialization, optimize cost	Split modules, add observability, prune deps, keep monolith sane.
5 devs	Tactical leadership shift	Start next hire pipeline, tech roadmap, security baseline.

Build the MVP without creating chaos

Keep it simple. One app + one DB + staging pipeline is enough right now. Defer complexity until patterns are clear, but modularize to keep change cheap. Instrument early with logs/metrics to speed up debugging.

Helpful internal reads on lightweight deployment choices and ops hygiene:

First 3 hires: who, when, how

Full-stack generalist — reduces your context-switching; ships UI→API.
Backend/infra-leaning dev (as needed) — owns DB, performance, deployments.
T-shaped product-minded dev — drives features end-to-end with UX sense.

Principles: hire when your velocity is blocked by your time; use real PR reviews as the interview bar; onboard with one bug + one feature in week one.

Security & reliability (minimum viable baseline)

Salted/hashed passwords; never roll your own crypto.
Role-based access and least privilege.
Error logging + alerts (crashes, spikes, 5xx).
Daily backups with restore test.
Simple incident runbook (who/what/rollback).
MFA/SSO for admin access as early as possible.
Track vendors and access (list, owners, offboarding).

Related internal reads for reliability basics:

Communicate like a co-founder

Write a 3-page architecture doc: modules, data flows, key decisions, known risks.
Send a weekly tech update: shipped, blockers, debt, upcoming decisions.
Tie features to outcomes and timelines; make trade-offs explicit.
Keep a lightweight diligence pack ready: architecture overview, dependencies, KPIs, vendor list, contingency plans.

How to implement now (this week)

Audit your week (30 min) List your last 7 days into: shipping / emergent / ignored-leadership. Identify one activity to drop and one to protect.
Draft architecture doc v0 (60–90 min) Modules, data flows, stack, 3 open decisions. Share for comments.
Set your security floor (60 min) Confirm hashing, MFA for admin, backups + restore test, logging + alerts. Create a one-page incident runbook.
Prep a hire-as-onboarding task (45 min) One contained bug + one scoped feature for candidates/new hires.
Adopt the Stage Map Compare intended vs actual focus every Friday. Adjust next week’s plan accordingly.

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